1. Field of the Invention
The present invention relates to electrical connectors and, more particularly, to an electrical connector having an overmolded housing.
2. Brief Description of Prior Developments
One method of manufacturing electrical enclosures for use in a harsh environment, particularly automotive, is to overmold metal electrical current carrying elements, generally referred to as terminals, with one of any number of engineering resins; thus producing an electrical enclosure with an integral electrical connector. Overmolding by itself does not, however, produce a perfectly sealed device. As the plastic cools and shrinks after molding, micro gaps can form between the metal and the plastic in which fluids can wick or leak. In cases where environmental sealing is required, such as for a fuel tank electrical connector, expensive secondary operations, such as potting or gaskets, are necessitated.
A process called an A2 treatment has been developed as a dry-pack free solution for moisture sensitive plastic surface mount packages. Unlike most lead frame surface treatments, A2 is an ultra-thin inorganic coating which is electro-deposited on metallic surfaces to provide coupling for polymetric adhesion. U.S. Pat. No. 5,343,073 discloses lead frames in integrated circuit (IC) packages having chromium and zinc alloy coatings. U.S. Pat. No. 5,728,285 discloses an A2 treatment, but in a semiconductor on a circuit board as a protective coating; not in an electrical connector and not to provide a sealing function.
A method for improving the adhesion of metal to plastic is desired to improve sealing and help the device meet stringent government regulations for hydrocarbon vapor emissions. A treatment is desired to promote the adhesion of molding resins to metal electrical current carrying elements in an overmolded electrical connector. There is an expectation that increased adhesion will greatly improve sealing. In the case of a fuel flange, permeation of hydrocarbon vapors to the environment are desired to be reduced. In the case of overmolded electrical connectors generally, expensive secondary potting operations are desired to be eliminated.